arch/x86/kvm/irq.c

   1 /*
   2  * irq.c: API for in kernel interrupt controller
   3  * Copyright (c) 2007, Intel Corporation.
   4  * Copyright 2009 Red Hat, Inc. and/or its affiliates.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  17  * Place - Suite 330, Boston, MA 02111-1307 USA.
  18  * Authors:
  19  *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
  20  *
  21  */
  22
  23 #include <linux/export.h>
  24 #include <linux/kvm_host.h>
  25
  26 #include "irq.h"
  27 #include "i8254.h"
  28 #include "x86.h"
  29
  30 /*
  31  * check if there are pending timer events
  32  * to be processed.
  33  */
  34 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
  35 {
  36         if (lapic_in_kernel(vcpu))
  37                 return apic_has_pending_timer(vcpu);
  38
  39         return 0;
  40 }
  41 EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
  42
  43 /*
  44  * check if there is a pending userspace external interrupt
  45  */
  46 static int pending_userspace_extint(struct kvm_vcpu *v)
  47 {
  48         return v->arch.pending_external_vector != -1;
  49 }
  50
  51 /*
  52  * check if there is pending interrupt from
  53  * non-APIC source without intack.
  54  */
  55 int kvm_cpu_has_extint(struct kvm_vcpu *v)
  56 {
  57         /*
  58          * FIXME: interrupt.injected represents an interrupt whose
  59          * side-effects have already been applied (e.g. bit from IRR
  60          * already moved to ISR). Therefore, it is incorrect to rely
  61          * on interrupt.injected to know if there is a pending
  62          * interrupt in the user-mode LAPIC.
  63          * This leads to nVMX/nSVM not be able to distinguish
  64          * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
  65          * pending interrupt or should re-inject an injected
  66          * interrupt.
  67          */
  68         if (!lapic_in_kernel(v))
  69                 return v->arch.interrupt.injected;
  70
  71         if (!kvm_apic_accept_pic_intr(v))
  72                 return 0;
  73
  74         if (irqchip_split(v->kvm))
  75                 return pending_userspace_extint(v);
  76         else
  77                 return v->kvm->arch.vpic->output;
  78 }
  79
  80 /*
  81  * check if there is injectable interrupt:
  82  * when virtual interrupt delivery enabled,
  83  * interrupt from apic will handled by hardware,
  84  * we don't need to check it here.
  85  */
  86 int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v)
  87 {
  88         if (kvm_cpu_has_extint(v))
  89                 return 1;
  90
  91         if (!is_guest_mode(v) && kvm_vcpu_apicv_active(v))
  92                 return 0;
  93
  94         return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
  95 }
  96
  97 /*
  98  * check if there is pending interrupt without
  99  * intack.
 100  */
 101 int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
 102 {
 103         if (kvm_cpu_has_extint(v))
 104                 return 1;
 105
 106         return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
 107 }
 108 EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 109
 110 /*
 111  * Read pending interrupt(from non-APIC source)
 112  * vector and intack.
 113  */
 114 static int kvm_cpu_get_extint(struct kvm_vcpu *v)
 115 {
 116         if (!kvm_cpu_has_extint(v)) {
 117                 WARN_ON(!lapic_in_kernel(v));
 118                 return -1;
 119         }
 120
 121         if (!lapic_in_kernel(v))
 122                 return v->arch.interrupt.nr;
 123
 124         if (irqchip_split(v->kvm)) {
 125                 int vector = v->arch.pending_external_vector;
 126
 127                 v->arch.pending_external_vector = -1;
 128                 return vector;
 129         } else
 130                 return kvm_pic_read_irq(v->kvm); /* PIC */
 131 }
 132
 133 /*
 134  * Read pending interrupt vector and intack.
 135  */
 136 int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 137 {
 138         int vector = kvm_cpu_get_extint(v);
 139         if (vector != -1)
 140                 return vector;                  /* PIC */
 141
 142         return kvm_get_apic_interrupt(v);       /* APIC */
 143 }
 144 EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 145
 146 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 147 {
 148         if (lapic_in_kernel(vcpu))
 149                 kvm_inject_apic_timer_irqs(vcpu);
 150 }
 151 EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 152
 153 void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 154 {
 155         __kvm_migrate_apic_timer(vcpu);
 156         __kvm_migrate_pit_timer(vcpu);
 157 }
 158
 159 bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
 160 {
 161         bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
 162
 163         return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
 164 }